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An efficient Channel Estimation Technique of OFDM-Base Space-Time Coded Wireless LAN Systems

  • Kim, Dong-Ok
    • Journal of information and communication convergence engineering
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    • v.2 no.2
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    • pp.61-66
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    • 2004
  • This paper presents a way to maximize transmission efficiency and reception ability through transmission diversity technology, which can be adapted to wireless multimedia Wireless LAN system. The presented method is a comparative analysis between a case where parameter a for time average is 0.3.1 with consideration of channel presumption with two types of rms delayed spread, which is 50nsec. 150nsec, for the performance analysis of STTC (Space-Time Trellis Code) adopting time-space ciphering method appropriate for MIMO channel, and performance in the case where presumed channel value from long training column section is applied to according frame in a single frame. The result showed that BER brought SNR improvement of l.0dB in $10^{-3}$ when a was 0.3 than adopting only the long training column, and showed increase of general performance improvement for the sake of time average rather than the case without.

An Integrated Process for the Separation and Purification of Biologically Active Proteins from Human Urine (인뇨로부터 유용단백질의 통합 분리정제 공정)

  • 김기용;정광회문흥모
    • KSBB Journal
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    • v.8 no.3
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    • pp.287-294
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    • 1993
  • For the purpose of combining the purification processes for several biologically active proteins form human urine, an efficient integrated fractionation procedure has been investigated. The procedure was started by concentration with ultrafiltration and pH precipitation followed by a selectable combination of chromatography on gel filtration, adsorption, ion exchanger, affinity, and reverse phase column. By this process, the purified urokinase, epidermal growth factor and albumin migrated as a single band on SDS-polyacrylamide gel electrophoresis and were fully active. The recoveries of these purified proteins were 48%, 17%, and 46%, respectively.

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Comparison of steels via SMAW and MIG welding methods under industrial loads

  • Soy, Ugur
    • Steel and Composite Structures
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    • v.11 no.3
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    • pp.225-232
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    • 2011
  • In this study, the deflection and deformation behaviours of IPN80 steel beam and column were investigated under the different industrial loads. Single-sided welds were applied to IPN80 steel beams using shielded metal arc (SMAW) and metal inert gas welding (MIG) method in the form of T-type. After that, the performance of SMAW and MIG welded joints were identified using beam bending test under 500 and 3000 N loads. SMAW and MIG methods were compared with each other to understand the deflection and deformation behaviours of the welded steel structures. Lower deformation and deflection were obtained in MIG welded steel beams. The results show that, steel beams welded MIG method has higher load capacity than SMAW welded ones. MIG welding method is more reliable than the SMAW method for the combining performance and load capacity.

Seismic Performance Assessment of RC Circular Column-Bent Piers Subjected to Bidirectional Quasi-Static Test (이축방향 유사정적 실험에 의한 이주형 철근콘크리트 원형 교각의 내진 성능평가)

  • Chung Young Soo;Park Chang Kyu;Lee Beom Gi;Song Hee Won
    • Journal of the Korea Concrete Institute
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    • v.17 no.1 s.85
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    • pp.121-128
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    • 2005
  • A RC column-bent pier represents one of the most popular piers used in highway bridges. Seismic performance of reinforced concrete (RC) column-bent piers under bidirectional seismic loadings was experimentally investigated. Six column bent-piers were constructed with two circular supporting columns which were made in 400 mm diameter and 2,000 mm height. One single column specimen was additionally made to comparatively evaluate the seismic response of RC column-bent piers. Test parameters are different transverse reinforcement and loading pattern. These piers were tested under lateral load reversals with the axial load of $0.1 f_{ck}A_g$. Three specimens were subjected to bidirectional lateral load cycles which consisted of two main longitudinal loads and two sub transverse loads in one load cycle. Other three specimens were loaded in the opposite way. Test results indicated that lateral strength and ductility of the latter three specimens were generally bigger than those of the former three specimens. Plastic hinges were formed with the spall of cover concrete and the fracture of the longitudinal reinforcing steels in the bottom plastic hinge of two supporting columns for the former three specimens. Similar behavior was observed in the top and bottom parts of two supporting columns for the latter three specimens.

Recovery of Intracellular Enzyme Using Phage Lysogen and Expanded Bed Adsorption (Phage Lysogen과 Expanded Bed Adsorption을 이용한 세포내 효소의 회수)

  • 장우진;윤현식구윤모
    • KSBB Journal
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    • v.11 no.6
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    • pp.663-668
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    • 1996
  • In the production of recombinant protein using E. coli, phage lysogen system can be usefully applied for simultaneously achieving protein production at high cell concentration and recovery by cell disruption in the same bioreactor. A major drawback of this system is that the intracellular product and complex broth components are mixed together in culture broth and hence purification efficiency is reduced. With the E. coli double-lysogen system, the expanded bed adsorption is very useful because the pretreatment processes in a routine bioseparation process can be done in a single column operation, and therefore may contribute towards lowering the operating cost of overall recovery/purification process. In the operation of EBA, it has been observed that the change in broth feed volume does not influence much the protein recovery in a tested range. The amount of protein adsorption per mL of resin was increased from $3.44{\times}106unit to 5.28{\times}106unit$ by doubling the column length. By two-fold increase of the column diameter, the ratio of protein concentration in eluent to that in feed was increased from 0.8 to 2.1. It is concluded from the present investigation that the increase of column length and diameter is necessary to enhance the protein adsorption amount per volume of resin and protein concentration in the eluent. The development of resins with various physical properties will be necessary for more extensive application of EBA.

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Development of Analytical Method for Fenoxanil in Agricultural Products Using GC-NPD and GC/MS (농산물 중 Fenoxanil 잔류성 시험법 개발)

  • Kim, Gyeong-Ha;Ahn, Kyung-Geun;Kim, Gi-Ppeum;Hwang, Young-Sun;Lee, Young Deuk;Choung, Myoung-Gun
    • The Korean Journal of Pesticide Science
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    • v.19 no.4
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    • pp.345-353
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    • 2015
  • The aim of this study is to develop residue analysis method for fenoxanil, a MBI (melanin biosynthesis inhibitor) propionamide fungicide, had mainly been used to control rice blast, and disease of other crops, fruits, and vegetables by using GLC/NPD and GC/MS. Extraction with acetone and partition with n-hexane/dichloromethane (80/20, v/v) were performed from hulled rice, soybean, Kimchi cabbage, green pepper, and apple, then column clean-up with florisil was applied. Mean recoveries were 82.2%-109.1% with less than 7.2% of coefficients of variation and limit of quantitation was set at the concentration of 0.04 mg/kg from the five agricultural products through the determination by GLC/NPD equipped with DB-5 capillary column and single laboratory validation. As a confirmatory method, GC/MS selected ion monitoring (SIM) was set from m/z 125.0, 188.9, and 293.0. Developed method is expected to apply the single residue analysis of fenoxanil in agricultural products.

Retention Behaviors of Natural Gas Components on a Single Column by Gas Chromatography (기체 크로마토그래피에 의한 단일 컬럼상에서 천연가스 성분의 머무름 거동)

  • Choi, Yong-Wook;Choe, Kun-Hyung;Lee, Dai-Woon
    • Analytical Science and Technology
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    • v.7 no.3
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    • pp.329-338
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    • 1994
  • The retention behaviors of natural gas components were studied on a single column by gas chromatography. The dead time, $t_0$ was obtained by using extrapolation of homologous series to determine capacity factors. The plots of retention data for homologous series and carbon number at different temperatures were shown to converge into a single point, which point was determined as a dead time. The results of the effect of temperature on the column efficiency for n-butane exhibited the plate number, N incerased with temperature, but the resolution among the fast eluted components decreased. The adsorption enthalpy (${\Delta}H^0{_{ads}}$) for each component on 28% DC 200 stationary phase was determined, and in order to investigate the retention behaviors of natural gas components the regression analysis of log $t_R$, log k' and log ${\alpha}$ vs. van der Waals volume(Vw), molecular connectivity index(X) and hydrophobic fragmental constant(f) were carred out. Good correlation was found between log k' vs. Vw, and log k' vs. f. The correlations between the physical properties of natural gas and the physical parameters were investigated by the linear regression analysis. The relationships between Vw vs. molecular weight and heating value(${\Delta}H_{comb}$), X vs. boiling point, and f vs. molecular weight, boiling point and heating value exhibited the high correlation coefficient more than 0.99. Using the regression equation between the heating value of natural gas and Vw the predicted heating values from $C_6$ to $C_{10}$ showed good agreement with those reported in the literature within 0.2% relative error.

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Purification and Characterization of Xylanase from Bacillus sp. A-6 (Bacillus sp. A-6의 Xylanase의 정제와 특성)

  • Choi, Suk-Ho
    • Microbiology and Biotechnology Letters
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    • v.37 no.2
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    • pp.147-152
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    • 2009
  • A xylanase was purified from the culture supernatant of Bacillus sp. A-6 by using ultrafiltration and ion exchange chromatography on the column of SP-Sepharose using 5 mM acetate buffer, pH 5.0. The xylanase was eluted from the column at the concentration less than 0.05 M NaCl. The eluted xylanase was shown to be a single protein band in SDS-PAGE. Zymogram analysis indicated that the protein band in SDS-PAGE had the enzyme activity to hydrolyze oat spelt xylan. The molecular weights of the xylanase were 15,000 based on SDS-PAGE and 14,100 based on gel filtration chromatography. Thin layer chromatography showed that the xylanase hydrolyzed oat spelt xylan into xylobiose and high-molecular-weight xylooligosaccharides. The relative activities of the heated xylanase decreased to 80% at $40^{\circ}C$ after 7 hr and less than 40% at $60^{\circ}C$ after 1 hr.

Enrichment of Lithium Isotopes by Cation Exchange Chromatography (양이온 교환 크로마토그래피에 의한 리튬 동위원소의 농축)

  • Kim, Dong Won;Kim, Chang Suck;Choi, Ki Young;Jeon, Young Shin;Jeong, Young Kyu;Park, Sung Up
    • Analytical Science and Technology
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    • v.7 no.2
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    • pp.201-204
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    • 1994
  • Cation exchange column chromatography of lithium was carried out to investigate the lithium isotope separation in aqueous ion exchange system. A Pyrex glass column of $50cm{\times}6mm$ inner radius with a water jacket was used as the separation column in experiment. Upon column chromatography using hydrochloric and succinic acid mixtures as an elunent, single separation factor, ${\alpha}$, 1.0068 was obtained. From the experiment, it was found that $^6Li$ was enriched in the resin phase and $^7Li$ in the solution phase.

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Identification of progressive collapse pushover based on a kinetic energy criterion

  • Menchel, K.;Massart, T.J.;Bouillard, Ph.
    • Structural Engineering and Mechanics
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    • v.39 no.3
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    • pp.427-447
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    • 2011
  • The progressive collapse phenomenon is generally regarded as dynamic. Due to the impracticality of nonlinear dynamic computations for practitioners, an interest arises for the development of equivalent static pushover procedures. The present paper proposes a methodology to identify such a procedure for sudden column removals, using energetic evaluations to determine the pushover loads to apply. In a dynamic context, equality between the cumulated external and internal works indicates a vanishing kinetic energy. If such a state is reached, the structure is sometimes assumed able to withstand the column removal. Approximations of these works can be estimated using a static computation, leading to an estimate of the displacements at the zero kinetic energy configuration. In comparison with other available procedures based on such criteria, the present contribution identifies loading patterns to associate with the zero-kinetic energy criterion to avoid a single-degree-of-freedom idealisation. A parametric study over a family of regular steel structures of varying sizes uses non-linear dynamic computations to assess the proposed pushover loading pattern for the cases of central and lateral ground floor column failure. The identified quasi-static loading schemes are shown to allow detecting nearly all dynamically detected plastic hinges, so that the various beams are provided with sufficient resistance during the design process. A proper accuracy is obtained for the plastic rotations of the most plastified hinges almost independently of the design parameters (loads, geometry, robustness), indicating that the methodology could be extended to provide estimates of the required ductility for the beams, columns, and beam-column connections.